-LRB- CNN -RRB- -- A Delaware pediatrician has been indicted on 471 felony counts in the alleged sexual abuse of his patients , prosecutors announced Monday .

The Sussex County grand jury indictment accuses Dr. Earl Bradley , 56 , who has had a practice in Lewes , Delaware , for more than 10 years , of victimizing 103 children -- all but one girls . The charges range from rape and sexual exploitation of a child to endangering child welfare and assault .

Delaware Attorney General Beau Biden told CNN Radio the indictment is based on `` video and digital evidence '' seized from Bradley 's home and medical practice in December . Authorities have not ruled out additional charges , he added .

`` The reality is that as a prosecutor , the rules prohibit me from telling you exactly how I feel -- and I 'm feeling a great deal today , '' Biden said .

Bradley also has medical licenses in Pennsylvania , New Jersey and Florida . Authorities have said they have contacted officials in those states .

He was initially arrested and charged in December .

Bradley 's attorney , Eugene Maurer Jr. , said he would base his client 's defense on mental health .

`` Most of the evidence in this case comes from videotapes -- it 's kind of hard to argue with videotapes , '' Maurer said , adding , `` The issue in this case is going to come down to his mental health at the time . ''

Biden said Bradley will be arraigned within four to six weeks .

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Dr. Earl Bradley faces 471 counts in the alleged abuse of 103 children

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Indictment is based on `` video and digital evidence , '' official says

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Doctor also has licenses in Pennsylvania , New Jersey , Florida